It is an object to create an illuminating system which, compared to conventional solutions, permits glare-free illumination combined with flexible construction and compact dimensions.
An illuminating system of flexible shape comprising at least one LED is specified. The LED is disposed on a flexible carrier material, an optic being provided that permits uniform, directed and/or glare-free light emission.
Compared to the prior art, the illuminating system is of flexible shape, i.e., bendable, and by virtue of the optic emits directed light with no glare effect, while at the same time, individual points of light are substantially undiscernible. The illuminating system additionally features high integration of the LEDs and variability in terms of its lighting capabilities. In particular, drops in emitted radiation intensity between adjacent LEDs are eliminated or at least greatly reduced. In other words, the individual points of light represented by the LEDs are converted into a glare-free light line or light area. Radiation is able to emerge particularly uniformly along this light line or from this light area. Novel light-emitting devices are thereby obtained that are suitable not only for illumination, but also for display, for example of information on monitors, traffic signs or advertising spaces, or for highlighting (backlighting). Its very small dimensions also make the illuminating system a natural choice for recessed lighting. Due to its flexibility, the illuminating system can be used on curved surfaces or can be deformed in open space through the addition of suitable mechanisms or motion devices (rods, ropes, tires, etc.).
It is especially advantageous under these circumstances if the optic is configured as a separate component, particularly one that is separate from the LED. In particular, the separate optic can be distinct from an encapsulant for a semiconductor chip of the LED. By virtue of the replaceable optics, the illuminating system can be variably adapted to different lighting and illumination tasks by changing said optics.
Several preferred embodiments of the optics are feasible, and can advantageously be combined with one another. For example, the collimation, guidance and equalization of the light is effected by means of a lens and/or an optically active medium (film, glass, fluid, etc.), which can be mounted spacedly or non-spacedly with respect to the LED. Thus, the optic can be embodied, for example, by a lens optic, particularly by Fresnel lenses. Fresnel lenses are distinguished in particular by their flat construction. This facilitates the design of an illuminating system with a very small overall height.
In a preferred embodiment, the overall height of the illuminating system is 10 mm or less, particularly 5 mm or less. The overall height can also be reduced further, and can be 4 mm or less, preferably 3 mm or less, particularly preferably 2 mm or less, for example 1.5 mm or less.
The lens optic can also be made of a rigid material, such as glass, for example. Also advantageous, however, are other exemplary embodiments in which the optic is formed by a nano- or microstructured film or by macrostructures in the film, such as convexities, corrugations or knobs. The film variant notably has the advantage of enabling the overall size of the illuminating system to be kept particularly small, while at the same time permitting high flexibility, especially mechanical flexibility. Rigid components (LEDs, lenses, etc.) can be incorporated by giving them a suitable structural shape and linking them together in a quasi-flexible arrangement (“chain line”).
In a preferred embodiment, a microstructured film has in a lateral direction, i.e., along a main direction of extension of the film, a structure having structure sizes of 500 μm or less, preferably 100 μm or less, particularly preferably 10 μm or less. The radiation emitted by the at least one LED during the operation of the illuminating system can thus be shaped in a simple and reproducible manner.
In a preferred embodiment, a nanostructured film has in a lateral direction a structure having structure sizes of 1000 nm or less. Further preferably, the structure size can be in the range of the emission wavelength of the associated LED in the material of the film, particularly between 0.2 times and five times the emission wavelength in the material of the film. Such a film makes it possible to influence the radiation characteristic of the illuminating system, for example by diffraction effects, and adapt it to a predetermined radiation characteristic of the illuminating system.
Such a particularly microstructured or nanostructured film can be regularly structured, particularly periodically and recurrently in one or more spatial directions, or it can be irregularly structured.
A fluid can also be used, however, in which case uniform, directed and glare-free light action is obtained as a result of the refractive index differential between air and fluid. The use of fluids is advantageous particularly in achieving broad flexibility.
The use of rigid materials can also be advantageous, however. Particularly in cases where the optic is implemented as a lens system, glass lenses or lenses made of similar materials are advantageous due to their ease of fabrication. In this case, the flexibility is preferably furnished by having the rigid optic consist of a plurality of individual parts whose position in relation to the LEDs nevertheless remains unchanged, even, notably, on deformation of the illuminating system.
Preferred exemplary embodiments of the illuminating system can further comprise a holder for the optic and/or at least one lamp envelope, particularly a tube, a (deep-drawn) film or a molded part, the holder and the envelope being so configured as not to present an obstacle to deformation of the illuminating system.
In a preferred improvement, the lamp envelope is formed by at least one element from the group consisting of molded part, tube, film and deep-drawn film.
In a preferred embodiment, the holder comprises at least two support elements, which are preferably disposed diametrically opposite each other. The optic is supported on the carrier material by means of these elements.
It has been found to be particularly advantageous if the optic is mounted in such a way that its position in relation to the LED remains substantially unchanged during deformation of the illuminating system.
The illuminating system preferably employs flat LEDs, particularly DRAGON®, TOPLED®, PointLED® and/or SIDELED® type LEDs, which give the illuminating system the preferred flatness. DRAGON type LEDs manufactured by Osram Opto Semiconductors GmbH are characterized in particular by high radiant power at an electric power consumption of 100 mW or more. These are consequently high-power LEDs. TOPLED type LEDs manufactured by Osram Opto Semiconductors GmbH notably have a preferred direction of emission that is perpendicular or substantially perpendicular to a mounting plane of the LED. In the case of a SIDELED type LED manufactured by Osram Opto Semiconductors GmbH, emission by the LED preferentially occurs primarily along the mounting plane. PointLED type LEDs manufactured by Osram Opto Semiconductors GmbH are notable in particular for their compact construction. The radiation characteristic of these LEDs is comparable to that of a punctiform light source.
Further preferably, the LEDs of the illuminating system are implemented as surface-mountable components. Surface-mountable components are also known as SMD components (SMD=Surface Mountable Device). Such components are easier to mount.
It is generally advantageous if the LEDs are implemented as colored and/or color-changing. Such LEDs make it possible to emit radiation that produces a colored, for instance red, blue, green or mixed-color, impression to the human eye. In particular, the LEDs can comprise plural, for instance three, LED chips that emit radiation in mutually different regions of the spectrum, for instance in the green, blue and red spectral regions. The illuminating system can further be equipped with a combination of different LEDs, for example ones that differ as to spectral characteristic.
In a preferred variant embodiment, the carrier material used is a film conductor and/or a flexboard, thus yielding a flexible illuminating system with an extremely small overall height. It is further advantageous to mount the LEDs on the carrier material directly, i.e., without a housing (COF: Chip on Flexboard). The overall size can be further minimized, according to another variant embodiment, through the use of height-optimized, particularly active or passive electronic, components, for example height-minimized resistors and/or drivers, particularly film resistors, hybrid resistors or the like.
To improve heat dissipation from the LEDs, preferably at least one thin cooling element, particularly a cooling plate, of high thermal conductivity is provided. The dissipation of heat can further be improved by filling the lamp envelope or the molded part with a high thermal conductivity material (metal, filled plastic, ceramic platelets, etc.). In the case of LEDs having a high power density, the dissipation of heat by the integrated cooling plate preferably takes place directly on an external heat sink, i.e., without an insulating plastic lamp housing. In this case, the external, for example rigid, heat sink can also be only partially formed and magnetically attached to the cooling plate. In particular, the heat sink can be formed from flexible corrugated sheet metal and attached directly to the plate, thus bringing about functional unification with regard to the tasks of holding and cooling by the cooling plate. Through this optimization of thermal management, the light output of the illuminating system can be improved further without altering its reduced installation space.
The flat and flexible implementation makes it possible to configure the illuminating system as a flexible, flat light strip. To this end, it is particularly preferred if a lamp housing is configured as a hollow profile bar of substantially rectangular cross section, in which the LEDs are adjacently disposed and form a common light-emitting area. In terms of production engineering, such a bar can advantageously be produced for example as an extruded profile made of a plastic, for example PMMA. The light strip is preferably extendable in segments (according to the arrangement of the electrical circuits) as the application requires.
In a preferred embodiment, the hollow profile bar has an interior space that is designed to receive the LEDs and is closed endwise, preferably sealingly, by an end piece or by a plug-type electrical connector system (plug or socket). It is preferred, in this case, for this element to be configured such that in the state of being mounted on the hollow profile bar, at least one lateral face extends flush with at least one lateral face of the hollow profile bar. After the light strip has been extended to suit the application, the strip can thus be closed off, preferably sealingly, by means of the end piece or the plug-type electrical connector system. The illuminating system can thus be adapted particularly easily to specific requirements within broad limits.
To mount the illuminating system, for example on a ceiling, the floor, the wall or a piece of furniture, the hollow profile bar, in a preferred exemplary embodiment, is insertable form-lockingly into a mounting profile. It is advantageous in this case if the hollow profile bar comprises at least one projection that engages in at least one guide channel of the mounting profile, or if the hollow profile bar comprises at least one guide channel in which the at least one projection of the mounting profile engages.
In an alternative exemplary embodiment, the cooling plate or the mounting surface is magnetically configured for the purpose of mounting the illuminating system.
According to a further alternative exemplary embodiment, the side walls of the mounting profile comprise at least one channel in which a roughly U-shaped, fixedly disposable holder for mounting the illuminating system form-lockingly engages.
The flat and flexible implementation further makes it possible to configure the illuminating system as a flexible, pixel-type flat lamp equipped with a multiplicity of LEDs. For example, the flat lamp can be implemented as a preferably active display, particularly for moving images. Such a flat lamp or flat display is suitable for placement on curved surfaces having potentially multiple, mutually parallel or obliquely convergent axes of curvature with different, potentially negative, bending radii.
The flat lamp can be cut into individual rectangles and the electrical connections re-established by means of a connecting element (X connector). In terms of production engineering, the manufacture of the illuminating system can easily be automated and is suitable for large-volume runs, e.g., for the production of light-emitting wallpaper, advertising spaces and large-area displays. For example, the illuminating system can include one LED for each pixel, in which case the emitted radiant power in the red, green and blue regions of the spectrum can be controlled mutually separately by means of the LEDs. Alternatively, a plurality of LEDs emitting radiation in different regions of the spectrum can be provided for each pixel. A display capable of full color reproduction can be produced in a simplified manner in this way.
The illuminating system can be freely focused by varying the curvature. An extremely broad range of emission angles can also be obtained.
According to a preferred exemplary embodiment, the LEDs are controllable individually via a control device, particularly a bus, making it possible to obtain varied light effects, for example colors of light, accents or light dynamics and optical displays, for example of still or moving images.
Further advantages, preferred embodiments and utilities of the illuminating system will emerge from the exemplary embodiments described hereinafter in conjunction with the figures. Therein: